All posts tagged Hurricane

From the Arctic leveling yet another challenge to all-time record lows for sea ice, to a ridiculously long spate of hotter-than-normal temperatures for Alaska, to Hermine — which appears to be readying to drop 20 inches of rain over parts of the Southeast — there’s a ton of concerning climate news today. Let’s get to it.

Storms, Mega-Dipoles, and Shattered Sea Ice

A few weeks ago, big storms of near-record intensity started ripping through the Arctic. These storms saw numerous pressure dips into the 960-millibar range. These severe systems raked the ice with gale-force winds, heavy seas, and rainfall. A vulnerable ‘arm’ of ice extending out from the central Arctic toward Wrangel Island began to disintegrate under these multiple insults.

(The two frames above provide a good visual of the most vulnerable Arctic Ocean melt regions for early to mid-September. These primarily compose the Siberian side of the Arctic and run on toward the Pole. A mostly detached and storm-battered region of sea ice north of Wrangel Island [left frame] is likely to see continued losses through mid-September. At the same time, another vulnerable lobe of ice extending from the Pole to the Laptev Sea [right frame] is seeing substantial thinning. As southerly winds pick up later this week over the Barents and Greenland Seas, the Atlantic side of the Arctic [lower right portion of right-hand image] may also take a final blow or two before refreeze starts to kick in. Images provided by: LANCE-MODIS. Date for images: September 1, 2016.)

Meanwhile, another melting wedge running out from the Pole toward the Laptev Sea was increasingly wracked, showing severe losses along the ice edge even as large openings expanded, stretching in toward the Pole. As a result, major late-season drops in Arctic sea ice area and extent measures began to show. Unfortunately, the damage had only just begun.

(Neven’s Mega-Dipole featured a burly high-pressure system over the Pacific side of the Arctic as strong storms continued to rage across the Atlantic side on August 29th. The combined force of these systems helped further damage the already weakened sea ice as warm winds blowing between them pulled heat up from Siberia, generating a late-season temperature spike over the Arctic Ocean. Image source: Earth Nullschool.)

Strong winds blew between the juxtaposed low- and high-pressure systems. This convergence sucked an intense pulse of warm air up from the south, not only providing a severe blow to the ice from gales and waves, but also injecting a surge of late-season heat into the High Arctic. In addition to the damage being done to the two melt arms, the whole of the remaining contiguous ice was driven in one big push toward the Canadian Arctic Archipelago — a shove that has now likely resulted in the complete separation of the thinned near-Wrangel ice from the pack even as large polynya (or holes) opened up within 10 kilometers of the Pole.

(A late-season temperature spike in the region above 80° North Latitude is helping to generate a surge in ice losses during early September. Image source: DMI.)

All this pushing and shoving and storming and low and high pressuring in the context of never-before-seen Arctic warmth has brought most of the major measures within range of beating out 2007 as second-lowest extent on record by mid-September. Meanwhile, a few of the measures are now making serious challenges to the 2012 record-low marks.

Over the coming days, the various high-pressure systems are predicted to shift more toward the Siberian side of the Arctic. Meanwhile, storms are expected to gather around Greenland, with some hitting the 970 to 980 mb range as they circulate up from the North Atlantic. Warm air is expected to funnel in from the Barents and Greenland Seas even as the region north of Greenland starts a cooling trend.

This hot-cold juxtaposition combined with ongoing pressure from storms, winds, and waves should continue to damage and expel the most vulnerable sections of ice in the near-Pole region and on toward the Laptev as well as the detached ice floes near Wrangel Island. Additional losses in the range of 150,000 to 300,000 square kilometers or more over the coming seven days are entirely possible. If this happens, it would be a rather severe rate of loss for early September all on top of a year that, on average so far, has seen lowest-recorded sea ice extents for the January-to-August timeframe and remains on track to hold that low mark through year-end.

An Amazingly Hot Year for Alaska

We should be very clear that despite all the storms and other weather drama going on over the Arctic Ocean, the primary cause for severe sea-ice losses is a record-hot world in which a lion’s share of the temperature rise is occurring over the far northern latitudes. And not too far from the melting Arctic sea ice, another Arctic region is also getting a big dose of this record heat.

This year, Alaska appears set to exceed all previous marks for warmest temperatures ever recorded during an annual period for the state:

Alaska with more days in the above normal tercile in 2016 that either 2014 or 2015 – the 2 warmest years on record. pic.twitter.com/teBcXIuyuU

(Through August 27, Alaska had experienced zero cooler-than-typical days, 22 days of relatively normal temperatures, and 218 days in which temperatures were in the top third of all daily averages. It’s a record that makes previous all-time hot years 2014 and 2015 look somewhat cool by comparison. Image source: Climatologist Brian Brettschneider.)

As climatologist Brian Brettschneider recently found, above, the number of days featuring temperatures in the top third of measurements included nearly nine out of ten of all days so far during 2016 and through August 27th. This extreme Alaskan heat has already exceeded the number of warmer-than-normal days during record-hot years 2014 and 2015. With four months in 2016 still remaining, and with the Arctic Ocean opening up to its north, it appears that Alaska is about to blow these previous record years out of the water.

(Sea-surface temperatures surrounding Alaska are between 3 and 5 degrees Celsius above average. Such extreme ocean heat should help keep temperatures abnormally warm over the state for at least the next couple of months and continue to add to a period of record heat during 2016. Note that the graphic above shows temperature departures from normal ranges, not absolute temperature values. Image source: Earth Nullschool.)

La Niña is settling in, though. This would normally provide some hope that temperatures in Alaska might start to fall off a bit, but right now, the local ocean waters surrounding Alaska are extraordinarily warm. It’s as if the Pacific ‘hot blob’ that plagued the U.S. west coast in 2014 and 2015 has shifted north toward Alaska in 2016. This climate change-related warm-water feature is likely to continue to create a warm surface temperature bias for the state over the next couple of months.

20 Inches of Rain Possible for Parts of the Southeast

Moving south and away from the various heating and melting in the Arctic, we find yet another big rainstorm brewing in the moisture-stacked atmosphere of the Gulf of Mexico. In this case, unlike the big deluge that roared through Louisiana during early August, this collection of towering thunderheads has a name — Hermine.

(Hermine, which may produce severe flooding over the U.S. southeast in the coming days, barrels toward Florida in this National Hurricane Center satellite animation.)

Punching up to minimal hurricane status early in the afternoon (EST) on Thursday, Hermine is predicted to make landfall along the big bend of Florida (pushing in 3-8 foot storm surges), track north into Georgia and then run up along coastal South Carolina, North Carolina and Virginia. Along this path, 4-10 inches of rainfall are expected with local amounts hitting as high as 20 inches.

Hermine is expected to produce storm total rainfall accumulations of 5 to 10 inches over portions of northwest Florida and southern Georgia through Friday, with possible isolated maximum amounts of 20 inches. On Friday and Saturday, Hermine is expected to produce totals of 4 to 8 inches with isolated maximum amounts of 10 inches possible across portions of eastern Georgia, South Carolina, and eastern North Carolina through Saturday. These rains may cause life-threatening flash flooding.

As with past rain-bomb events this year, Hermine is churning through a record-hot atmosphere and feeding on overall record-high moisture levels. Sea-surface temperatures over the Gulf of Mexico and particularly over the Gulf Stream region of the Atlantic near the eastern seaboard are extraordinarily hot. Ocean surfaces off coastal Virginia, for example, now rival those along the eastern Gulf at near 30 degrees Celsius (86 F). The result is that a ton of storm energy in the form of heat and moisture is blanketing a big swath from Florida to the U.S. northeast. In this heat- and moisture-rich environment, even the high forecast rainfall amounts have a potential to be exceeded.

(Ocean temperature and currents map for 8/30/16. Water temperatures in the Gulf Stream off the U.S. east coast are near 30 C [86 F] or about 4 C hotter than normal. This means there’s almost as much potential storm fuel for a hurricane off the eastern seaboard as there is in the northeastern Gulf of Mexico — fuel that can both provide energy for extreme rainfall events related to Hermine and for a possible rapid reintensification. Image source: Earth Nullschool.)

Moreover, Hermine is predicted retain a degree of strength over land due to this fuel even as it is expected re-emerge over water along the North Carolina sounds and then track toward the hot Gulf Stream. Along this track, the storm is expected to restrengthen and lash coastal North Carolina, Virginia, Delaware and New Jersey before it skirts Long Island and Massachusetts. Given the hot ocean waters, some models even show Hermine bombing into a significant storm with ECMWF model runs earlier today highlighting a potential for a 969 mb storm center off Delaware on late Saturday.

Fortunately, the storm center is currently predicted to remain offshore after re-emerging over open waters on Saturday. However, the large circulation of the system means that any reintensification will likely see some of the storm’s related rain bands swirling out over the mid-Atlantic and northeast coasts.

******

So from big sea ice losses to record heat in Alaska, to what’s shaping up to be another extreme rain event for the U.S. southeast, the climate hits just keep on coming. It’s all a part of the context of climate change that’s been steadily settling in over the past few decades, which paints a rather obvious picture of ongoing climate shifts and alterations to expected weather patterns — to include the loss of sea ice, the intensity of heat over Alaska and the severity of rains falling out during storms like Hermine.

On Monday afternoon, Typhoon Vongfong was a moderate strength category 2 storm churning through the open waters of the Western Pacific. These waters, warmed to 1-2 degrees Celsius above the 20th Century average by a merciless human heating of the world’s atmospheres and oceans provided extra fuel upon which the still growing storm could feed.

In the airs above, conditions grew more and more favorable, wind shear dropped and an upper level high pressure system built over the strengthening storm. These conditions allowed Vongfong to draw deep from the newly heightened pool of potential storm energy of the hotter than normal Western Pacific. The result was that Vongfong’s pressure rapidly dropped to 900 mb, just 5 mb shy of super typhoon Haiyan’s peak strength. Wind speeds surged by nearly 80 mph inflating Vongfong to a powerful 180 mph monster.

Vongfong is now the 6th Western Pacific storm to reach extreme category 5 intensity this year — the strongest tropical cyclone on record for all of 2014 thus far.

Forecast Track Brings Vongfong’s Heavy Rains Over Japan

Thankfully, this human-warming amplified monster storm still remains well away from the densely populated land masses of the Philippines and Japan as it explores the absolute upper limits of maximum storm intensity. But, by this weekend, Vongfong is expected to come slamming into the island chain near Okinawa as a strong category 3 storm and then to ride into Japan as a category 2 storm, bearing strong winds and dumping copious amounts of rain over the already water-logged archipelago.

Japan, during the month of September, received extraordinary rainfall totals, in some places breaking all-time records. Now, during October, a 1-2 punch of Western Pacific storms threatens to bring more flooding to already saturated regions. As of today, official forecasts for locations along Vongfong’s track could receive more than 10 inches of rain by this weekend. A heavy addition to already record fall totals for the archipelago nation.

Conditions in Context

Overall, the Pacific Ocean has been far warmer and stormier than is typical. Today shows the broader Northern Pacific at an extraordinary +1.18 degrees Celsius above the already hotter than normal 1979 to 2000 average. And this extra heat seems to be heightening storm formation in regions where storm-feeding atmospheric instability and moist air abound. In total, the North Pacific Basin has seen 38 tropical cyclones this year, just shy of the annual average of 40-45 and with nearly three months left to go in the year. Some of these storms have been among the most intense on record with fully six super typhoons spawning in the Western Pacific and with the Eastern Pacific seeing its 4th strongest storm ever to form for that basin — category 5 Hurricane Marie.

Though most of the intense heat anomalies are to the north and east, almost all regions show above average water temperatures. The waters along the typical typhoon track running toward Japan, for example, range from 0.5 to 1.5 C above average just east of the Philippines to 1 to 3 C above average in a zone east of Taiwan and just south of Japan.

The ghosts of record Pacific Ocean heat content may well be coming back to haunt us…

Very powerful near Category 5 Ita is now bearing down on the Australian Coastline. Regions near where the center makes landfall, projected to be near Cape Flattery, could experience 155 mph sustained winds with gusts in excess of 185 mph and storm surges in excess of 25 feet. Interests throughout North Queensland should remain abreast of what is a very powerful and dangerous storm capable of producing record or near record effects.

(For reference, a category 5 storm has a wind speed intensity of 156 mph or greater.)

Major rainfall events are not uncommon in the Solomons. But what occurred as a result of current and abnormally intense heat-spurred Pacific Ocean convection is. For the massive shield of thunderstorms that spawned Ita also dumped one meter (1000 mm or 39.4 inches) of rainfall during a three day period over some sections of this tropical island chain. The far-reaching floods ruined roads, bridges, buildings and forced the cessation of strip mining operations in interior sections.

(Thunderstorms associated with the newly forming Ita boil over the Solomon Islands on April 3rd and 4th. Some locales received single-day rainfall totals in excess of 18 inches with three day measures topping 1 meter. Image source: LANCE-MODIS.)

The Solomon Islands lie just east of New Guinea and are on the southern edge of what is currently a very deep, hot pool of water — one that appears to be in the process of rushing eastward. There, over waters ranging from 85 to 87 degrees Fahrenheit (29-30 degrees Celsius, or about 1-2 C above average), Ita had her genesis in a shield of convection forming along the hot pool’s southern flank.

Slow Westward Trek

After lingering for days over the Solomons, Ita gradually shifted southwestward, churning on into the Coral Sea and reaching category 1 intensity by April 8th. Water temperatures throughout the region remained well in excess of 80 degrees, more than enough to fuel rapid intensification. By late April 9th, many models showed Ita potentially reaching category 4 or 5 intensity before roaring into northern Queensland.

Concerns were raised about both projected storm intensity and projected track. Clockwise circulation of a slow-moving but very powerful storm could pile a very significant storm surge along the Queensland cities of Port Douglas and Cairns. Northern locations could experience very intense and prolonged storm conditions including heavy rainfall, extreme coastal flooding, and winds in the range of 90 to 155+ mph over a tightly compact zone.

Cape Flattery, Cooktown and Port Douglas, sparsely populated towns of between 2,000 and 3,000 residents, respectively, are likely to bear the brunt of the storm. But Cairns lies only a little further south along the storm track and boasts fully 150,000 residents — a more densely populated region that could also see extreme impacts.

Bombification

By early April 10th, favorable environs and extremely warm water temperatures in the Coral Sea had resulted in the rapid intensification predicted. By 1600 Eastern Time in the US, Ita had bombed out to a 155 mph monster storm with a lowest central pressure around 921 mb, exploding from a Category 1 to a near Category 5 storm in less than 48 hours, as it headed toward the Australian coastline at an excruciatingly slow pace of 6 mph SSW forward motion.

It’s worth noting that a 921 mb reading is very low and may justify a new winds speed of closer to 165 mph or more considering how compact this storm. Early model runs had projected peak intensity at 920 mb and around 165 mph wind speeds. That said, ITA remains over open water and retains a very compact wind field, so further intensification is possible before land interference begins to disrupt circulation.

Even now, conditions may seem disturbingly tranquil along the coastline. Winds there are currently running in the range of about 20-30 mph. But gale force winds lurk about 100 miles offshore and the intense, hurricane force, winds are not fare behind. The most intense winds, of up to 155 mph sustained with 185 mph gusts, are in a tight band just about 10-20 miles from the center. It is regions within this band of clockwise onshore flow where most damaging effects are likely to be witnessed.

Ita is expected to maintain Category 4-5 intensity all the way through to land-fall sometime tomorrow. As such, storm surge flooding in excess of 25 feet is likely near where the center makes landfall. A storm of similar strength, Typhoon Mahina, brought a 45 foot storm surge ashore near Bathurst Bay in 1899. It is the same region where Ita is expected to make landfall sometime tomorrow.

This storm surge of 45 feet ties Bangladesh for the highest storm surge on record anywhere in the world.

Mahina made landfall with a minimum central pressure of 914 mb. Ita would only need to drop another 10 mb to exceed that mark. But, if it does, a world storm surge record could be set to fall.

UPDATE: Ita shows some slight weakening in both satellite and pressure estimates. Pressures (NOAA) as of about 7 PM were around 926 mb with maximum sustained winds still estimated in the range of 150 to 155 mph. Australia’s Bureau of Meteorology maintains ITA at 907 mb and CAT 5. Still a very powerful storm.

UPDATE: As of 9 PM EST, US, Ita continued to show some signs of slight weakening. NOAA now shows Ita as a 931 mb storm, while Australia’s Bureau of Meteorology puts it at 914 mb. No cause for comfort, as yet, since these pressure estimates are well within the range of a strong CAT 4 or CAT 5 storm.

Perhaps more ominous, however, is a slight job to the south. Too early to call but if a more southerly track continues, locations such as Cairns may be in for more of an impact. Still too early to call.

As per the recent VMAX wind profile Ita’s gale force winds are now on shore. Measurements are in knots. In this measure maximum sustained winds are just into CAT 5 status (138 kts). Image source is NOAA.

UPDATE: Ita came ashore as a Category 4 storm with effective one minute sustained winds in excess of 135 mph and a ten minute sustained wind of 120 mph near Cape Flattery in Queensland. Pressures at landfall were in the range of 935 to 948 mb. Ita has continued to track just inland and is now just west of Cooktown. Interaction with land has continued to degrade Ita, which as of 12 PM EST was estimated at Category 3 intensity.

In the southeast this year, rain follows rain follows rain. Now a tropical system may be preparing to add its own moisture to the already very wet mix.

The river of upper level airflow called the Jet Stream begins an almost due south movement at the Arctic Circle near the Northwest Territory and Canadian Arctic Archipelago. The atmospheric river dives down over Central Canada and into the Great Lakes region. Continuing ever southward, it finally encounters a wall of warmer air setting up near the south Tennessee border where it speeds up and turns eastward, joining another Jet Stream flow coming in over the Rockies.

Riding along these convergent Arctic and Pacific Jet Stream flows are a number of wet and stormy impulses. Because this deep north to south dip has been in place over the Eastern and Central US for much of the summer, storm after storm has continued to impact a large region from Missouri to New Jersey southward through the Carolinas and then again southwestward along through Georgia and the Gulf Coast states. This persistent stormy pattern, a result of a slow, wavy, stuck Jet Stream, which is, in turn, caused by sea ice and snowfall loss in the Arctic, has pushed rainfall totals 20 inches or more above the yearly normal in some locations. It has delivered extraordinarily moist storms that dump inches of rainfall in just a few hours. And it resulted in some regions of Missouri receiving four months worth of rainfall in just one week.

In the above water vapor image, provided by NOAA, you can see the storms riding along the south frontal boundary of this Jet Stream trough through the Dakotas, Montana, Nebraska and Colorado then down into Texas, turning eastward through the Gulf Coast States and then surging north along the US East Coast.

Yesterday, this pattern delivered a powerful storm complex to Pennsylvania and New Jersey — flooding roads, knocking out power and dumping as much as six inches of rain. Now, the Jet Stream has driven further south, pushing the frontal boundary over the Gulf Coast and US Southeast.

But as if the convergent flows of the Jet Stream delivering very powerful storms, as if the stuck weather pattern keeping this storm-delivering trough over the Eastern US for months, and as if the human-added atmospheric heat amping up the hydrological cycle and spurring more intense rain events were all not enough, we now have a large, moist tropical weather system moving in and threatening to become entangled in an already very wet pattern.

As of this morning, the National Hurricane Center had issued an advisory for a tropical system in the western Caribbean predicting a 60% likelihood of tropical storm formation over the next several days. The system is a large, sprawling and disorganized mass of thunderstorms and moisture moving toward the north-west at 10 to 15 mph. A circulation appears to be trying to form in a region near the densest thunderstorms. The system is predicted to move toward the northwest until it is eventually captured by the frontal boundary at the leading edge of our deeply sagging Jet Stream. Should this mix-up occur, a tropical weather system and potential tropical cyclone will have again combined with an Arctic originating air-mass over the Eastern US, setting the stage for a rather intense and widespread rainfall event.

If there are some reading this analysis and thinking that it rhymes somewhat with set up for Superstorm Sandy, they wouldn’t be entirely off the mark. Until recently, it was less likely that tropical systems would combine with polar originating air masses over the US. The troughs originated and faded rapidly, only infrequently coming into dramatic collisions. But now, with the Jet Stream increasingly settling into a stuck pattern (spurred by human caused warming and sea ice loss) and seeming to favor trough development over the continental US and not over the ocean, such collisions are far more likely.

With the current system, unlike Sandy, rain appears to be the primary concern for now — not storm hybridization, expansion, and superstorm development. These are not on the radar. But we are still very early in storm development and we don’t yet know how powerful the slowly organizing tropical system will become. What we have right now is a large, and potentially strengthening package of tropical moisture setting its sights on an already soaked US southeast.

So the risks at the moment are for a potential major flooding event on the five to seven day horizon as the tropical system continues to track northwestward until it is pulled into the stormy flow of the Jet Stream trough. At that point, it is predicted to dump a heavy load of moisture and rain over the US southeast.

Current predictions from NOAA reflect uncertainty in storm development and track and, at the moment, call for 3-5 inches of rainfall from the Gulf Coast States through Georgia and the Carolinas over the next 5-7 days. Local amounts, however, could be much higher, on the order of 8 inches or more. Such an event would intensify an already severe flood problem over this large area, likely resulting in major and widespread flooding.

Any significant wind field of 40 mph or more would also likely result in a mass of fallen trees. The ground in this region is saturated with moisture, making it harder for tree root systems to grip the soil. So it takes much less wind to blow them down. Widespread power outages due to trees falling over power lines is, therefore, also a potential threat for this system.

Given the current position of the Jet Stream and uncertainty over potential storm strength and track, this situation could rapidly develop into a dangerous event for the southeastern US or we could end up with a storm system making landfall closer to Texas and Mexico. So we’ll be closely watching storm strength and path over the coming week.

UPDATE:

Tropical weather system 92 L is starting to exhibit some cyclonic turning:

(Earth. See that massive swirl of clouds with arms stretching up into the Arctic and back across the Atlantic Ocean? Yes, that’s Sandy.)

This year was already the worst extreme weather year ever recorded. Fires, heatwaves, a monster Derecho and a devastating drought together would have made 2012 one for the record books. The one saving grace, it seemed, was that hurricane season hadn’t significantly added to an already severe problem. That was before Hurricane Sandy slammed into the US Northeast causing what many think will be in the range of 10-20 billion dollars in damage. If total damage estimates exceed 20 billion, Sandy will be one of the five most costly hurricanes in US history.

Sandy was nothing if not unprecedented. Never has the Northeast seen this kind of storm so late in the season. Never has New York and New Jersey been subject to such a high level of ocean flooding over such a broad area. According to CNN’s chief meteorologist: “There’s no one that’s not 300 years old that has seen anything like this.” That’s just a finer way of saying that there is no record for a storm like Sandy ever occurring in this region of the country. And, in many cases, there’s no record for a storm like Sandy occurring period.

What made Sandy so unique? In two words: climate change. We’ve seen northeastern Atlantic Ocean storms where powerful troughs combine with hurricanes in ways that create a much stronger storm. The last time such a thing happened was during the 1991 ‘Perfect Storm.’ But that storm formed over the open waters of the Atlantic and only caused damage as it brushed New England with the powerful squall lines and heavy surf it cast off. In the case of Sandy, the Perfect Storm came ashore far further south and west than is usually possible.

Sandy’s Global Warming Ingredients

Since 1991, atmospheric changes and alterations to the Earth’s physical characteristics have been taking place that make storms like Sandy more and more possible. These ‘ingredients’ include increasing ocean temperatures, changes in the jet stream, and the receding boundary of Arctic Sea Ice.

To understand how these changes made it possible for a storm like Sandy to have such a devastating effect on the US Northeast and Mid-Atlantic so late in the season, it helps to follow the life of the storm that became Sandy…

Like so many other hurricanes, Sandy was born of the tropical Atlantic. She started as a pulse of thunderous rain storms swirling off the coast of Africa. This tropical wave slowly gathered energy from the hot tropical Atlantic as she moved west, gradually twisting into the classic coma shape as she entered the central Caribbean.

(GOES weather satellite Image of Sandy from October 22. Sandy is already large for a tropical system. But Sandy will soon grow even larger by combining with other storms to the north.)

Ocean heat content for the South Atlantic and Caribbean was abnormally high this year. Most of this added heat content came from human caused global warming. In many regions, temperatures were 2-3 degrees above average. This meant that, for a storm like Sandy, these waters were about as warm as they would have been two to three weeks earlier during a typical season of the 20th century. This added energy increased the likelihood that the storm would form in the first place. It also gave the storm more capacity to strengthen even in an environment of increased wind shear.

As Sandy tracked northward, she plowed through Jamaica and hopped over the eastern tip of Cuba. Maintaining significant strength as a category two storm, Sandy grew to a large size, boasting a tropical storm wind field in excess of five hundred miles in diameter. Hovering off the coast of Florida, Sandy was about to enter the second stage of her development.

Two systems to the north would play key roles in Sandy’s growth and path. Both were products of new ‘blocking patterns’ that have emerged as regular weather events during the past decade. ‘Blocking patterns’ occur when the jet stream makes deep swoops down from the Arctic and into the mid and lower latitudes. These swoops make giant wave-like patterns in the jet stream. They also create a huge amount of atmospheric inertia. The result is that weather patterns tend to be more persistent. In the under-belly of a blocking pattern, one can expect abnormally hot and dry conditions to persist over long periods of time. In the frontal down-slope of the blocking pattern, one can expect abnormally cool, wet, and stormy conditions. The peaks of these blocking patterns tap the tropics and the troughs tap the Arctic.

According to Dr. Jennifer Francis, these blocking patterns have emerged as a result of sea ice loss in the Arctic. The receding edge of the sea ice pulls air northward changing the shape of the jet stream from that of a rippling halo to that of a circle of sine waves.

The new blocking pattern that had established itself over the central US allowed a powerful cold front to sweep southward, both lending energy to Sandy via strong temperature and pressure gradients and steering Sandy first northward, then pulling her in toward the Mid-Atlantic coast. A second aspect of the blocking pattern emerged in the form of a new high pressure system that has tended to form recently over Greenland. This particular high pressure system blocked the path of Sandy northeastward, shoving Sandy back up against the frontal trough that ended up lending her so much strength.

(A visible satellite shot of Sandy beginning to combine with a powerful Arctic cold front. The massive trough of cold air is outlined in blue. Sandy is in the red circle. To the northeast is a blocking high backing in over Newfoundland. Note the extraordinary size of the combined trough and Sandy.)

As Sandy began to touch the trough’s strong, cooler winds, her tropical storm wind field spread out, eventually reaching 900 miles in diameter. In addition, Sandy found herself cloaked in the trough’s rain shield. This shield helped to prevent the worst effects of wind shear which, at times, was powerful enough to rip a normal storm apart.

Sandy’s encounter with the Arctic-born cold-air trough caused her to explode in size and as she moved north, she pummeled the Outer Banks of North Carolina and Coastal Virginia from 300 miles off shore. What strength she lost at her core was multiplied manifold in the expanding reach of her effect. North Carolina and Virginia coasts experienced impacts usually reserved for those in the direct path of a Hurricane — powerful winds, heavy rains, and storm surge flooding. Roads were washed out, dunes were breached, homes were flooded. Water rises exceeded seven feet in some places.

(Sandy taps hotter than normal Atlantic Ocean water in final rush to the coast. At this point, Sandy is the largest tropical cyclone ever recorded in the Atlantic Ocean.)

Yet Sandy was still hundreds of miles away, biding her time for the final rush to shore. And in this critical time period, global warming again played its hand. Sandy was now moving parallel to the Virginia coast. In normal years, water temperatures would begin to drop off here, sucking energy from the storm. This year, though, water temperatures had heated to 5 degrees Fahrenheit above normal through, the year after year, heat trapping effects of human emitted greenhouse gasses. Sandy drank deep from this added heat and, as the Arctic-born trough began to pull Sandy in to shore, she intensified.

Maximum sustained winds reached 90 mph, tropical storm force wind diameter reached 1000 miles, hurricane force wind diameter reached 200 miles, and the pressure fell to an unprecedented 940 millibars. Sandy was now a storm for the record books. A storm that was the largest tropical cyclone ever to form in the Atlantic. A storm never seen before in this region of the world. A storm powerful enough to push ocean water nearly a mile inland up and down the Jersey coast. A storm mighty enough to create a nearly 14 foot water rise in New York City.

Without climate change, the storm may not have formed in the first place, the storm probably wouldn’t have reached category 2 strength or grown to such a large size, the storm would have not combined with such a powerful trough sweeping so far south, the storm would have not been blocked from going out to sea by the new Greenland/Newfoundland high pressure, the storm would not have strengthened so far north over abnormally hot waters, and the storm would have not been pulled into the coastline by the powerful blocking pattern caused by melting sea ice.

Sandy was, in all ways, the storm that climate change wrought. And since the pattern is now established for this kind of storm to happen now, it is likely that this kind of ‘300 year storm’ will happen again. Almost certainly with growing force and almost certainly within the next decade or two.

“Perhaps, if you are in your 60s or 70s or 80s, Sandy’s destructive forces are a once in your lifetime event. But younger generations—those of us in our fifties, and our children—will likely be looking at flooded coastal cities, devastated infrastructure, blownout power, and storm surges for the rest of our lives.”

(Graffiti scrawled on the side of a house flooded by Sandy. Image credit: here.)

Yesterday, a hurricane that had combined with a nor’easter and then tapped into both the powerful energies of an over-heated Atlantic Ocean and cold Arctic air seeping out through regions once encased in sea ice vented its fury on the New Jersey coastline. All up and down the Jersey Shore, community after community faced a historic storm surge born of a storm made far worse by climate change. A storm whose effects were the worst seen in this region of the US East Coast in 300 years.

Atlantic City seemed to bear the brunt of Sandy’s wrath. As early as Monday morning, the city’s coastal defenses were breached, its sea wall overwhelmed, its boardwalk washed away and its streets and homes subject to the pounding force and rush of storm waves. Residents of the barrier island community found themselves stranded as the rising tide cut off access to their community. Many fled to community storm shelters only to find the rising tide flooding these structures as well. Homes were ripped off their foundations and floated down the street or were swept into the raging Atlantic. At one point, a National Guard unit made a valiant effort to save some of those stranded by the storm. The effort was partly successful, but resulted in the loss and flooding of a number of pieces of military equipment. Overnight, the storm worsened, preventing any access to the storm-ravaged town and forcing its terrified residents to spend a water logged and fearful night alone and without public aid.

Just to the south of Atlantic City, Ocean City also faced Sandy’s terrible wrath. A seven foot water rise inundated the town and flooded its streets. As the water rose, 231 residents made emergency calls for help after refusing to heed evacuation orders. Though 50 persons were moved to escape the raging seas, miraculously no lives were lost. Almost as an after-thought Sandy parted with a 100 foot section of the Ocean City Pier.

Further north along the coast, Point Pleasant waged a valiant battle against rising seas all throughout the day. High waves and pressing tides battered the city’s beleaguered dune line. Finally, as the storm rushed in with the astronomical high tide, the dunes gave way and torrents of water rushed into the town’s streets. The city’s boardwalk was torn to shreds as boats were ripped from their moorings to float into the city where they were finally laid to rest on streets, lawns, or railroad tracks. In some places, water rushed nearly a mile inland. One home, three quarters of a mile from the shore, flooded with more than a foot of ocean water in the first floor driven in by Sandy and the 8 PM high tide.

“I kept asking him [my husband], ‘Should we go on the roof?’ I was really scared,” said Rosemary, as their house flooded. “The force and the speed that the water was pouring down and pouring over, it was scary. It rose so fast. It just kept coming and coming.”

In another part of town, firemen bravely faced the rising waters, slogging through the chest-deep flood to reach stranded residents.

The word New Jersey governor Chris Christie used to describe the wide-spread and far-ranging devastation all up and down the Jersey coast was “unthinkable.”

“The idea … that you see homes in the middle of Route 35 southbound and northbound is just unfathomable,” Christie told reporters at a morning briefing.

A deadly and devastating storm, one that set records not seen in 300 years, dealt a terrible blow to New York’s coastal regions Monday.

The 940 millibar storm, the most intense for this region on record, pulled a 14 foot storm surge up Long Island Sound and into Naragansett Bay Monday evening. This intense pulse of water overwhelmed New York’s flood defenses, filling the great city’s subways, overwhelming the Battery area, and soaking New York City neighborhoods. Construction at the new World Trade Center site was inundated, underground subways; parking lots and shopping centers were flooded out.

Massive surges of water assaulted the US’s largest city from all sides. Naragansett, to the north spilled water into the city’s back side. Long Island Sound, to the south, funneled an amplifying pulse of water directly into the city’s heart. The massive storm surge rushed in through storm drains, sending water gushing up through sewers, fountaining out of man hole covers, until neighborhood after neighborhood looked out over flooded streets.

Above the city, the storm left the twisted wreckage of a crane dangling from a high rise apartment complex built for the affluent. Billionaires, who occupied the top four floors of the complex, were treated to a front row view of the wreckage — twisting and swaying in Sandy’s 90 mph winds. Transformer fires and electrical equipment explosions whelmed the night before leaving much of the city dark late Monday. Large sections of the city remained without power as first responders began to pick over the damage this morning.

Though New York City was assaulted by a host of troubles, much of Long Island and coastal New York also fell under the heavy blow of this monster storm. Storm surges left section after section of the coast assaulted by battering waves. In places, the dune lines or sea walls were breached, leaving communities vulnerable to the ravages of an angry sea.

Sandy’s fury inundated Breezy Point. The force of the storm was enough to flood first floors and foundations, ripping off debris and sloshing it together in a twisted, shambling mound of wreckage at the mercy of an angry tide. But the worst came in the form of an unexpected fire that leapt from house to house even as the flood waters swirled about. Fire fighters dragged hoses through the heaving water or piled into inflatable boats in a desperate attempt to combat the spreading inferno. NYPD personnel took to the water in scuba equipment to reach victims trapped in flooded, burning homes. As the water began to trickle out, homes burned to their foundations. In all, the fire claimed about a hundred structures. By sunrise, all that remained of a large swath of town was a pile of wet and smoldering debris. A scene that might remind one of last year’s Japan Tsunami or of Dante’s Inferno, depending on predilection.